Hydroperoxide Lyase (HPL) catalyzes the cleavage of hydroperoxide lipids to form six carbon volatile compounds and a 12-Carbon product. The C6-volatiles are responsible for the “green-note” flavour characteristic of plant products and have been discussed as playing a role in the defence response in plants. For example, the volatile aldehydes are known to exhibit anti-fungal (Vaughn et al 1993, J. Chem Ecol. 19:2337–2345), anti-bacterial and anti-insect (Matsui et al 1986, FEBS Let. 394:21–24) activities. The C12 compound gives rise to thaumatin a wound-related signalling compound. The cleavage of hydroperoxide lipids also produces jasmonic acid that is also involved in stress and disease resistance signalling. WO 00/00627 and Matsui (1986 FEBS Let. 394:21–24) describe increased expression of HPL in wounded plants.
The HPL gene has been cloned from bell pepper (WO 00/00627; Matsui et al. 1986, FEBS Let. 394:21–24), maize (WO 00/22145), banana (EP 0 801 133) and Arabidopsis (Bate et al., 1998. Plant Physiol. 117:1393–1400; WO 00/00627), and the preparation of expression cassettes to increase or decrease HPL expression within these plants is described. The HPL gene has been sequenced by the Arabidopsis genome sequencing project (Accession number: Z97339) and reveals an open reading frame interrupted by eight introns. However, there is no teaching of the characterization of the regulatory region of HPL.
As described herein, the upstream region of the HPL gene has been characterized and used to drive the expression of a gene of interest. Even though the HPL regulatory region is known to drive wound-, insect-, fungal-, and bacterial-induced expression, unexpectedly, it was observed that large portions of the HPL regulatory region and fragments thereof, resulted in constitutive expression of the gene of interest in a range of tissues and organs in the absence of any wound or stress treatment. Therefore, the present invention relates to providing a regulatory region capable of driving expression of a gene of interest.
It is an object of the invention to overcome disadvantages of the prior art.
The above object is met by the combinations of features of the main claims, the sub-claims disclose further advantageous embodiments of the invention.